As a typical one of the noncontact information media each incorporating an IC chip or IC module, there may be mentioned a noncontact IC card designed for communicating with external apparatus or equipment by making use of an electromagnetic or radio wave and microwave. At this juncture, with the phrase “IC card” used in this specification, it is contemplated that smart card, intelligent card, chip-in card, microcircuit (microcomputer) card, memory card, super card, multi-function card, combination card and the like are to be comprehensively covered, by “IC card”. It should further be mentioned that the shape of the noncontact information medium incorporating the IC chip is never restricted to the card-like shape. Accordingly, the noncontact information medium conceptually includes a so-called IC tag as well. Incidentally, with the phrase “IC tag”, it is intended to mean all the information storing mediums of postage stamp size or of subminiature size smaller than the former or coin-like shape so far as the functions similar to those of the IC chip can be realized.
The information input/output unit according to the present invention can advantageously be implemented as a reader/writer designed for use in combination with a close-fit-type noncontact information medium having a relatively short range of communication on the order of zero to several millimeters by taking advantage of electromagnetic induction inter alia. However, the mate for the communication with the information input/output unit is not always restricted to such noncontact information medium that is equipped with the IC chip. It is sufficient that the noncontact information medium is provided with at least the antenna through which communication with the reader/writer can be effected. By way of example, the mate for the communication with the reader/writer may be a booster which includes a coil(s) and a capacitor(s) and which extends the communication range of the noncontact IC card.
The readers/writers may be classified into a contact type species and a noncontact type species in accordance with the methods of communication with the noncontact information media such as the IC chip, the IC tag and others. Among them, the noncontact type reader/writer has advantageous features that no contact failure occurs because of the absence of contacts with the IC card, the reader/writer can be used movably with a distance in the range of a few centimeters to several ten centimeters and that the reader/writer exhibits remarkable insusceptibility to soil, rain and static electricity, promising thus an increasing popularity together with the noncontact information media for the not-so-distant future.
The noncontact IC card is designed to make available an electric power for operation from the radio wave received from the reader/writer through electromagnetic induction and exchange data with the reader/writer. The noncontact IC card includes an antenna (e.g. antenna coil) and an IC chip as discrete or independent members, respectively. The antenna serves for transmission/reception of radio wave with the reader/writer. The IC chip includes a nonvolatile memory and the like and is electrically connected to the antenna. Packaging of this type noncontact IC card encounters technical difficulty in electrically connecting minute-size terminals of the IC chip with the antenna. Besides, wire breakage is likely to occur in the interconnecting portions under the influence of a stress applied to the card which is intrinsically flexible. Further, there is required a base plate or substrate for holding the IC chip and the antenna, involving increase in the manufacturing cost. Additionally, the inspection of the electrical interconnections, the antenna and the IC chip for confirming the operation can be carried out only after the IC chip and the antenna have been packaged and interconnected, which means that the manufacturing efficiency is not to be satisfied.
Under the circumstances, an coil-on IC chip in which the antenna coil is incorporated in the IC chip (i.e., on-chip implementation) has recently been proposed in view of the demand for miniaturization of components and multi-functional purpose. The coil-on IC chip is advantageous in that the problems involved in the packaging can be mitigated because the antenna coil and the IC chip are electrically connected to each other already at the wafer level. Additionally, the coil-on IC chip allows the noncontact information medium to be miniaturized in various shapes. In particular, in view of the fact that the reader/writer is expected to be used as a function extending device for the personal computer without being restricted to the use as the credit card or the like known heretofore, it is conceived that the shape of the noncontact information medium is not limited to the card but implemented in numerous and various types of shapes for many applications by taking into account the miniaturization, maneuverability or manipulatabillty, maintainability, aesthetic appearance, user's preference and so forth.
The conventional reader/writer known heretofore however suffers a problem that the data communication with the close-fit-type noncontact information medium whose communication range is short as on the order of several millimeters (e.g. the noncontact information medium incorporating the coil-on IC chip described above) can not be performed in a satisfactory manner. Certainly, the reader/writer can perform communication with the noncontact information medium having a relatively long communication range on the order of several centimeters to several ten centimeters with a distance from the noncontact information medium. However, for effecting communication with the close-fit-type noncontact information medium, it is required that not only the noncontact information medium is fit closely but also the antennas of both the noncontact information medium and the reader/writer are positioned accurately on the order of several millimeters. Under the circumstances, the coil-on IC chip has not been put to practical use yet due to the difficulty in positioning the noncontact information medium.
Furthermore, the conventional reader/writer known heretofore also suffers a problem that the degree of freedom is less afforded in respect to the shape of the close-fit-type noncontact information medium. In this conjunction, it is noted that the shape of the conventional noncontact information medium having a relatively long communication range does not present any serious problem because it is intrinsically designed to communicate with the reader/writer with a distance therefrom. By contrast, the close-fit-type noncontact information medium can be implemented in various shapes because of susceptibility to miniaturization in general. However, it becomes more difficult to position and fit closely the close-fit-type noncontact information medium relative to the reader/writer although it depends on the shape (e.g. coin-like shape of the close-fit-type noncontact information medium). Needless to say, the conventional readers/writers are not in the position to handle a plurality of various close-fit-type noncontact information media having different shapes, respectively.